New water soluble sulfuric acid esters of leuco derivatives of indigoid vat dyestuffs



Patented Sept. 27, 1932 r I l PATENT.

WILHELMI BAUER, J'OSEF HALLER, AND L'UDWIG ZEH, F WIESDORF-ON-THE-RHINE,

GERMANY,ASSIGNORS TO GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y.,

A CORPORATION" OF DELAWARE NEW WATER SOLUBLE SULFUR-IO ACID ESTERS 0F LEUCO DERIVATIVES OF INDIGOID VAT DYESTUFFS I No Drawing. Application filed April 13, 1931, Serial no.52as91, a d in Germany April 23} 1930.

The present invention relates to new water-soluble sulfuric acid esters of leuco derivatives of indigoid vat dyestuffs containing nitro groups and to the dyeings and printings obtainable by means of said esters.

In accordance with the present invention sulfuric acid esters of leuco. derivatives of indigoid vat dyestufis containing nitro groups are prepared, which esters have affinity to animal and vegetable fibers and can be developed on the fiber to yield the dyeings of 'indigoid vat dyestuffs containing nitro groups.

The manufacture of our new sulfuric acid esters may be performed according to various methods. For example, the indigoid vat dyestuffs containing nitro groups may be treated with a metal, especially a heavy meta1, such as copper, zinc, iron etc. in the presence of a tertiary organic base, such as pyidine, homologues thereof, quinoline, dimethylaniline, hexahydrodimethylaniline etc.,

while leading sulfur trioxide through the reaction mixture, or while adding a reagent containing sulfur trioxide or being able to split off sulphur trioxide under the conditions of working, such as fuming sulfuric acid, chlorosulfonic acid, chlorosulfonic acid esters etc. Suitable organic solvents being inert to the starting materials, such as chlorobenzene, ortho-dichlorobenzene, etc. may be added to the reaction mixture. The reaction may be performed at normal or elevated temperature, say, for example, at a temperature between about 10 and about 100 (1, while applying about 5 to about 10 parts by weight of the heavy metal upon 10 parts by weight of the starting dyestufl' and more thanrtwo 40, molecular proportions of sulfur trioxide or of the agent containing sulfur trioxide, or being able to split off the latter (calculated on the sulfur trioxide available) upon one molecular proportion of the starting dye- 4 stuff. The amount of the tertiary organic base applied maybe variedin wide limits.

When working without the addition of a solvent inert to the starting material," we

prefer to apply the base in an amount sufficient to allow a good stirring of the reac-I tion mixture, for example, 5-10 parts by weight on one part by weight of the starting dyestufi. However, it may be mentioned that a great part of the base may be replaced by an organic solvent being inert to the starting materials, as mentioned above. 7

According to another feature of the invention the sulfuric acid esters of the leuco derivatives of the indigoid vat dyestuffs are prepared as described in application for Letters Patent Serial No. 529,892 of even date,- that is by reducing indigoid vat dyestuffs by means ofhydrogen sulfide in the presence of a tertiary organic base, especially a tertiary heterocyclic base or a hydrogenation product of a tertiary isocyclic organic base, at normal or slightly elevated temperature, and by esterifying the leuco derivative thus obtainable with sulfur trioxide or an agent containing sulfur trioxide or being able to split off the latter under the conditions of working, in the presence of a tertiary organic base. Obviously, the reaction may likewise be performed by simultaneously reacting upon the indigoid vat dyestuff with ,a mixture of a. base of the kind above referred to, sulfur trioxide or an agent containing sulfur trioxide or being able to split off the latter under the conditions of working, and of hydrogen sulfide, the reaction being performed in the same manner as described in the co-pending application Serial No. 529,892 of even date.

A third method of preparing the sulfuric acid esters in question is as follows The indigoid vat dyestuffs are reduced to the corresponding leuco derivatives by means of sulfurous acid in the presence of formic acid and of a tertiary organic base, such as pyridine, a homologue thereof, quincarrest Q ter and air (oxygen) should be avoided as far as possible.

The sulfuric acid esters thus obtainable most probably contained in their free form the grouping r V I V,

' O-SOaH o-sonz They are, especially in the form of their alkali metal-or ammonium salts, easily solublein water. They are nearly colorless or 001- ored compounds (generally weakly greyish or yellow to yellowish-red or black) and are reduced without saponification to the corresponding amino esters of the indigoid dyestuffs by treatment with alkaline reducing agents, for example, sodium hydrosulfite and a dilute aqueous caustic soda solution. By. oxidizing agents in an acid med1um,.for example,by an aqueous ferric chloride/hydrochloric acid solution or an aqueous alkali metal nitrite/hydrochloric.acid solution, the

esters are saponifiedwith the. formation of the starting dyestuffs. 7

I The new esterscan be used for dyeing or printing purposes in the manner known for dyeing and printing with water-soluble sul-' furic acid esters of vat dyestuffs. For example, they are dissolved in water, sulfur c ac d or acetic acid is added, wool 15 dyed 1n this bath and the dyeings are developed bytreat ing the wool with a dilute mineral acid (sul-V.

fume for example) m therpresence l dium, for example, with sodium hydrosulfite sodium nitrite or sodium'bichromate.

Otherwise, woolor cotton may be printed with a printing paste containing a watersoluble salt of the sulfuric acid ester and an alkali metal or ammonium nitrite, .where-. after the printings are developed 1n the usual manner in a. mineral acid bath. Likewise,

the sulfuric acid ester of the leuco indigoid vat dyestuff, ammonium thiocyanate or diethyltartrate, sodium chlorate and ammonium vanadinate. The printings are then steamed and soaped at the boil. The dyeings or printings thus obtainable are those corresponding to the starting dyestuffs containing free nitro groups.

The following examples illustrateour invention, without, however, restricting it thereto, the parts being by weight Ewample'l Into 200 partsof anhydrous pyridine 40 reaction mixture is poured into 1 ice water,; whereupon the pyridine salt of the ester separates. It is-filtered, dissolved in water with the addition of potassium carbonate, the so- 7 lution is filtered and salted out with potassium carbonate. An orange colored crystallme powder is thus obtained, easily soluble in-water. When treating the aqueous solution with acid oxidizing agents, for example, erilc chloride/hydrochloric acid, the starting dyestuff s recovered.' The new ester,

which most probably corresponds in its free form to the formula q dyes wool from an acid bath orange shades, which on treatment with acid oxidizing agents are converted into a corinth of good fastness properties. Likewise, the ester may be applied for V cotton printing purposes, yielding after oxidation corinth shades of good fastness properties, particularly to chlorine, light and washing. 7

When reducing the ester in an alkaline mein aqueous caustic soda solution, the corresponding amino leuco ester is obtained in form of a light grey powder, yielding on oxidationwith acid oxidizing agents a blackishgreen amino compound.

7 Ewample Q 60 parts of chlorosulfonic acid methyl ester are introduced while stirring into 100 parts of anhydrous pyridine and 500 parts of chlorobenzene at a temperature of 510 C. After replacing the air contained in the reaction vessel by carbon dioxide, 30 parts of 7 .7 -dinitrothioindigo (orange-brown powder dissolvin in'stron sulfuric acid with a violet coloration) and 21 parts of copper powder are added and the reaction mixture is stirred for about 3 hours, while leading carbon dioxide through the mixture and cans ing the temperature to rise slowly to about 3540 G.- The reaction mixture is filtered with suction and the residue washed with benzene. Then the residue is extracted with 3 corresponds to the formula (RSOaNa (isomer e The estercontains two nitro groups and can be retransformed to 7.7 -dinitrothioind1go by means of acid oxidizing agents.

Example 3 A thisatine chloride with 2.1-naphtho-oxythiophene, are finely powdered, mixed with 26 parts of copper powder and the mixture is introduced at about G. into a solution of parts of sulfur trioxide in 400 parts of anhydrous pyridine. The reaction mixture is stirred at about 25 C. for about 3 hours while excluding air. The est-er is isolated as described in Example 1. It most probably corresponds in its free form to the formula a. a C omfl 1 NH/ s The 5-nitro-6.9-dichloro 1.2 naphthisatine, the chloride of which is applied in this example, can be obtained by reacting with concentrated nitric acid upon 6.9-dichloro- 1.2-naphthisatine. It crystallizes from glacial acetic acid in the form of red needles,

OSOaH OSOaH i melting above 280 C.

Ewample 4 parts of chlorosulfonic acid are introduced into 800 parts of anhydrous pyridine, to'which mixture 30 parts of the dyestufi, obtainable by reacting upon the condensation product of 2.1-naphtho-oxythiophene and pa-ra-nitrosodiniethylaniline with 5-nttro oxythionaphthene, and 20 parts of copper powder are added. The mixture is stirred for one hour at room temperature and then two hours at 3035 C. while excluding air. After that, the mixture is poured into water and the ester isolated in the form of its potassium salt by salting out. It forms a weakly olive-green colored powder which color changes to a reddish-brown when oxidized with acid oxidizing agents in substance or on the fiber. The ester corresponds in its free. form most probably to the formulae- OSOBH 5-nitro-oxythionaphthene, applied for the manufacture of the starting dyestulf, is ob-f i taina-ble by substituting the 'chloro atom of 5-nitro-2-chlorobenzene-l-carboxylic acid by the radical of thioglycollic acid, treatingthe reaction product with. acetic 'anhydride and splitting off the acetyl group. 5-nitro-oxy-' thionaphthene crystallizes from alcohol in Weakly yellowish coloredleaflets, melting at 125 C.

Example 5 Sulfur dioxide is passed a-t'5-10" G. into 100 parts of anhydrous pyridine, until the increase of weight amounts to ten parts. 2.5 parts of formic acid are added,jand, furthermore, 10 parts of the finely powdered dyestufi, obtainable by reacting upon S-nitroisatine-alpha-chloride with 6.7-benzo-(Bz-4L' -chloro) -oxythionaphthene. The air the reaction vessel is then replaced by carbon dioxide and the reaction mixture stirred for half an hour at a temperature of 0., whereupon a clear yellowish-brown solution is formed. This solution is poured, while exeluding air, into .a mixture, obtained by slowly introducing 20 parts of chlorosulfonic acid into parts of pyridine. The tempera-ture rises to about 30 0., and the reaction mixture is kept at this temperature for about 2 hours. After that, the reaction mixture is poured into 200 parts of water, 40 parts of sodium carbonate are added, and the pyridine is removed by steam distillation. The resulting yellowish-red solution is filtered and the'sodium salt of the ester formed salted out by means of sodium chloride. It forms an olive colored powder, easily soluble in water with a yellow coloration and behaves towards oxidizing andreducing agents in the same manner as the product of Ex-' ample 1. The new ester corresponds in its free form to the probable formula osoan os 0311 Ewample 6 no r the temperature is slowly raised to 25 80 naphthene are introduced into 150 parts of anhydrous pyridine, containing parts of sulfurous acid. The mixture is then heated to 5060 0., after which 4 parts of formic acid 1 are stirred in slowly. The dyestuff dissolves withthe yellow coloration of its leuco derivative. The reaction mixture is further stirred for half an hour at 60 C. while exeluding air, and then poured into a mixture of 100 parts of anhydrous pyridine and parts of .chlorosulfonic acid methyl ester. During esterification the temperature is kept at 2530 (l, and then the reaction mixture is poured into dilute caustic soda solution. 25 The pyridine is distilled off by steam distillation, and the sodium salt of the leuco sulfuric-acid ester formed is salted out by means of sodium chloride. It most probably corre-,

'0 sponds to the formula i .(ISSO3Na 0\SOaNa ON o o I NH/ s It forms a yellowish-brown powder, yielding, when used for dyeing-or printing purposes, after oxidation with acid oxidizing agents a greenish black shade of good fastness properties.

Ewample 8 20 parts of sulfur dioxide are introduced into 200 parts of anhydrous pyridine, while cooling with ice. To this solution 5 parts of formic acid and 20 parts of the dyestuif, ob-

tainable by coupling 5-nitroisatine chloride with a-chloro-l-naphthol, areadded. The temperature is raised to C., until the dyestuff has dissolved with a yellow coloration. After cooling to 10 to -5 G., 40 parts of chlorosulfonic acid are added and the temperature is raised to 354:0 C. After about one hour the reaction mixture is so worked up in the usual manner, and the sodium salt of the leuco ester formed is isolated as described before. It forms a yellowish colored crystalline powder, easily soluble in water, being split up to the starting dyest-uif by means of acid oxidizing agents." The new ester corresponds in its free form most probably to the formula osoaa i I the action of 5-nitro=isatine-chloride on 2.1- naphtho oxythiophene, are stirred in the form of a fine powder into 300 parts of anhy-' drous pyridine. Anhydrous hydrogen sulfide is passed into this suspension at the ordinary temperature, until the dyestufi has completely dissolved in the form of the leuco compound. The excess of hydrogen sulfide is then displaced by carbon dioxide, and the solution is introduced, while excluding air, into an esterification mixture consisting of 200 parts of pyridine and 60 parts of chlorosulfonic acid, produced at 5-10" C. While continuing the passing through of carbon dioxide, the mixture is stirred at a temperature of about 30 C., until the esterification is complete. It is then poured into ice water, 50 parts of caustic soda solution of 33% strength and an excess of sodium carbonate are added, and the pyridine is distilled oil by means of steam. The remaining yellowish-brown solution is filtered, and the sodium salt of the ester separated by the addition of sodium chloride. The ester corresponds in its free form to the probable formula It is a yellowishbrown powder, which aissolves in water with a yellow coloration. On treatment with mineral acids in the presence of an oxidizing agent, the original dyestufi, a brown with a violet tinge, is recovered. The nitro group has accordingly been retained. l/Vhen sodium hydrosulfite is caused to act on the sodium salt of the ester in alkaline solution, reduction of the nitro group to the'amino group occurs, the color becoming lighter. The reaction product can be isolated by salting out in the form of a yellowish colored powder. On decomposition and oxidation, for example, with sulfuric acid and potassium 'dichromate, it yields av greenish-black.

Example 10 390 parts of 7 .7-dinitrothioindigo are stirred with a freshly produced ice cold solution of 68 parts of hydrogen sulfide in 1100 parts of anhydrous pyridine, first at 510 C.

and then at room temperature, until a yellowish-brown solution results, from which the dark colored leuco compound of the dinitrothioindigo'has in part separated. The reaction mass is then stirred at ordinary temperature and with the exclusion of air into an esterifying mixture consisting of 400 parts of chlorosulfonic acid and 2000 parts of pyridine. The chlorosulfonic acid may be replaced in this example by the same quantity of chlorosulfonic acid methyl ester.

The reaction mixture is worked up in the customary manner; The sodium salt of the 7 .7-dinitro-thioindigo-leuco sulfuric acid ester of the probable formula (iSOgNa (OlJSOaNa.

crystallizes from water in yellowish-brown leaflets and, on treatment With dilute mineral acids in the presence of an oxidizing agent and with the application of heat, reformsthe orange colored 7 .7-dinitro-dithioindigo.

Example 1 100 parts of the finely powdered vat dyestuff, obtainable by the action of a reactive alpha-derivative of 5-nitr0-6.7-benzo-(Bz-lAldichloro) -isatine (prepared by treating 6.7 benzo(Bz-1.4:-dichloro) -isatine With an excess of concentrated nitric acid at ordinary temperature) on 4.5-benzo-hydroxythionaphthene, are introduced at 5-10 G. into an esterification mixture consisting of 200 parts of chlorosulfonic acid and 1000 parts of pyridine. Anhydrous hydrogen sulfide is then led in at the same temperature. After about one hour, the dyestuff has passed into solution in the form of its leuco compound. The supply of hydrogen sulfide is then reduced and the temperature raised to 20-25 (1, until a test portion no longer oxidizes in the air in alkaline solution. The whole is then poured into much ice water and left to stand for some time until the pyridine compound of the ester has settled. This compound is isolated and converted into the sodium salt by reaction with caustic soda in the manner already described.

The compound thus obtainable corresponds most probably to the formula:

0 S OaNa O S OgNa OzN l 0- ll l C] NH/ s The following table shows some of-the leuco esters we have prepared and the shades of the dyeings or printings obtainable by means of said esters.

' Shades of dye- Leuco ester of jugs 5.5-dibromo-7.7-dinitroindigo Greenish-black The dyestu'lf obtainable from 5-bromo-7-nitroisa- Brown tine chloride 2.l-naphtho-oxythiopl1ene' The dyestnfi obtainable from 5-bromo,7-nitroisa- Black tine chloride alpha-anthrol The dyestufi obtainable from 5-bromo-7-nitroisa- Steel-blue tine chloride 1-chloro-2.3-naphtho-oxythiophone The dyestufi obtainable from 5-bromo-7-nitroisa- Blackish-violet tine chloride 4.7-dimethyl-5-chloro-oxythionaphthene The dyestufi obtainable from 5-nitro-9-chloro-l.2- nfiphthisatine chloride -l- 2.l-naphtho-oxythiop ene Brownish-blacl:

5.5-dichloro-7.7-dinitrothio-indigo Orange The dyestufi obtainable from 5.7-dichloroisatine Violet chloride 5-nitro-oxythionaphthene The dyestufl obtainable from G-methoxy-oxythio- Orange naphthene-alpha-l dimethylamidoanil 5- nitro-oxythionaphthene The dyestufl obtainable from fi-nitroisatine chlo- Reddish-violet ride nitro-oxythionaphthene The dyestulf obtainable from 8-chloro-L2-naph- Reddish-black thisatine chloride l- 5-nitro-oxythionaphthene The dyestufi obtainable from 2.1-naphthisatine Corinth chloride 5-nitro-oxythionaphthene 5.5-dibromo-7 .7 -dinitroindigo, which has been unknown up-to-date is prepared by treating 5-bromo-7-nitroisatine-alpha-chloride with hydrogen sulfide in chlorobenzene.

We claim:-- 7

1. The new sulfuric acid esters of leuco derivatives of indigoid vat dyestuffs containing nitro groups bound to any aromatic nucleus, said esters possessing in their free form the characteristic grouping SIOaH 80 E #3 t t ll OzN said ester being in the form of its alkali metal salts a weakly olive-green powder, easily soluble in Water, and being a valuable product for dyeing and printing purposes.

3. The new sulfuric acid ester having in its 2 free form the probable frmu1a:

SIO3H slOsH said ester being inthe form of its alkali metal salts an orange powder, easily soluble in water and being'a valuable product for dyeing and printing purposes.

In testimony whereofifwe .afiix our signa- '20 'LUDWVIG ZEH. 

